I'm curious about whether the anyone has noticed any brake boost effects from the use of the TA miniracks mounted to centerpull pivots. Seems that they should also add a bit of stiffness and reduce flexing. Hmmm, I may need to do some experimentation.
Charlie
Charles T. Young
Honeybrook. PA
<classicrendezvous@bikelist.org> Sent: Wednesday, March 13, 2002 5:24 PM Subject: Re: [CR]Bushings on centerpulls
> Yes, they aren't that hard to make, in fact rather
> simple. Lacking production machinery, they're just
> time-consuming. After we ran out of production "brake
> boosters" at Cupertino Bike Shop, we made a few more
> by hand from 1/8" or 3/16" aluminium plate. Sometimes
> we got creative with the shapes and did some special
> artwork to jazz things up on otherwise pedestrian
> brake sets. (The booster plate with a small Bernard
> Hinault portrait that went on the bike of a Peugeot
> amateur team racer traveling to France in 1981 was my
> personal favorite. Hopefully "The Badger" motif
> brought the rider good luck and iron nerves in the
> peloton.)
>
> It was tedious grunt work carving out the shapes, but
> as you say, the booster plates really improved the
> braking performance of the plastic-bushing Mafac
> Racers and other center-pulls by keeping the pivot
> points parallel under hard braking force from the
> handle & cable. Often we just put the booster plates
> on the front brake since equally hard braking on the
> rear locked up the wheel. Combined with some better
> brake pads, like Mathausers, this generally brought
> things up to par with the fancy Mafac Criteriums (?--
> if I recall the name correctly/) center-pulls that had
> the posts brazed onto the frame. Mostly, though, in
> those days using Campy sidepulls was a better overall
> equipment choice unless there was some overriding
> reason to use center-pulls (such as team sponsorship).
>
> Bill "one last pair of boosters in the vault" Bryant
> Santa Cruz, CA
>
>
>
> --- Original Message ---
> From: "James A Narlesky" <jim@alandavid.com>
> To: <RaleighPro531@aol.com>,
> <classicrendezvous@bikelist.org>
> Subject: Re: [CR]Bushings on centerpulls
>
> >Peter, Jan, et al.
> >
> >For Mafac brakes, the after market arched plate that
> connected just in front
> >of the bushings really makes a notable improvement in
> the feel and
> >modulation of these particular brakes. This fix
> limits the flex of the
> >calipers considerably. If someone were to make more
> of these there would not
> >be the perceived need for bronze bushings and I would
> bet that these arched
> >devices would be easier to make.
> >
> >Regards,
> >
> >Jim "Accountant, not a Machinist"Narlesky
> >San Jose, CA
> >----- Original Message -----
> >From: <RaleighPro531@aol.com>
> >To: <classicrendezvous@bikelist.org>
> >Sent: Wednesday, March 13, 2002 11:32 AM
> >Subject: Re: [CR]Bushings on centerpulls
> >
> >
> >> In a message dated 3/13/2002 2:15:23 PM Eastern
> Standard Time,
> >> heine@mindspring.com writes:
> >>
> >>
> >> > The plastic bushings on the Mafacs could be
> replaced easily. Hardware
> >> > stores have bushings, but the right size might be
> harder to find.
> >> > I've been thinking of machining the bushings -
> and they are bronze,
> >> > not brass, as far as I know (and so are the ones
> in the hardware
> >> > store). I haven't got around to it. Anybody
> interested? I can provide
> >> > specs.
> >> >
> >> > HOWEVER, the brakes work great even with plastic
> bushings, so I
> >> > haven't felt the need. Consider than the bearing
> surface on the large
> >> > pivots is much greater than the pivot bolt on a
> standard sidepull
> >> > (such as Campy NR), and even those don't seem to
> be a problem.
> >>
> >> My interest in doing new bushings would be to make
> the pivots a bit
> >tighter
> >> so as to limit arm movement under braking.
> >> Maybe it's a moot point anyway: if the pivots are
> tight then the arms flex
> >> enough to make it more trouble than it's worth?
> >>
> >> Pete Geurds
> >> Douglassville, PA
> >>
> >>
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